When I attach a second screen to my laptop and put V-Rep window on the second screen and after that i lock my pc (with WinKey + L) after I unlock it i find that V-Rep crashed and with the following error:

0x1bc3290 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1bc2ed0 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1bbfe40 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1318960 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1b2b0a0 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1b2b5b0 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.
0x1bc0790 void QWindowPrivate::setTopLevelScreen(QScreen*, bool) ( QScreen(0x1bd78b0) ): Attempt to set a screen on a child window.

Usually the crash is not instantaneous, if Ilock and unlock right after it is still running, but if I lock and I wait a little bit I find it crashed.

Hi. I had this issue before - I had to solve it by switching off my screen rather than locking which is not ideal. That being said, I think it has to do with the XServer on my system, if you get anywhere with this pls post, I will do the same.